Problem 6 - Department of Computer Sciencecannata/networking/Homework/HW1.pdf · # HW1.pdf #...

3
# HW1.pdf # Homework 1 # # UT EID: XXX999, UTCS username: XXXXXXXX # CS326e, Spring 2014, Dr. P. Cannata # Department of Computer Science, The University of Texas at Austin -- Problem 6 a) s m d prop / = seconds. b) R L d trans / = seconds. c) ) / / ( R L s m d end to end + = seconds. d) The bit is just leaving Host A. e) The first bit is in the link and has not reached Host B. f) The first bit has reached Host B. g) Want ( ) 536 10 5 . 2 10 56 120 8 3 = × × = = s R L m km. Problem 19 An example solution:

Transcript of Problem 6 - Department of Computer Sciencecannata/networking/Homework/HW1.pdf · # HW1.pdf #...

Page 1: Problem 6 - Department of Computer Sciencecannata/networking/Homework/HW1.pdf · # HW1.pdf # Homework 1 # # UT EID: XXX999, UTCS username: XXXXXXXX # CS326e, Spring 2014, Dr. P. Cannata

# HW1.pdf # Homework 1 # # UT EID: XXX999, UTCS username: XXXXXXXX # CS326e, Spring 2014, Dr. P. Cannata # Department of Computer Science, The University of Texas at Austin --

Problem 6 a) smd prop /= seconds. b) RLdtrans /= seconds. c) )//( RLsmd endtoend +=−− seconds. d) The bit is just leaving Host A. e) The first bit is in the link and has not reached Host B. f) The first bit has reached Host B. g) Want

( ) 536105.21056

120 83 =×

×== s

RLm km.

Problem 19 An example solution:

Page 2: Problem 6 - Department of Computer Sciencecannata/networking/Homework/HW1.pdf · # HW1.pdf # Homework 1 # # UT EID: XXX999, UTCS username: XXXXXXXX # CS326e, Spring 2014, Dr. P. Cannata

Traceroutes from two different cities in France to New York City in United States a) In these traceroutes from two different cities in France to the same destination host in

United States, seven links are in common including the transatlantic link.

b) In this example of traceroutes from one city in France and from another city in

Germany to the same host in United States, three links are in common including the transatlantic link.

Page 3: Problem 6 - Department of Computer Sciencecannata/networking/Homework/HW1.pdf · # HW1.pdf # Homework 1 # # UT EID: XXX999, UTCS username: XXXXXXXX # CS326e, Spring 2014, Dr. P. Cannata

Traceroutes to two different cities in China from same host in United States c) Five links are common in the two traceroutes. The two traceroutes diverge before

reaching China 72800 IN NS C.GTLD-SERVERS.NET.

Among all returned edu DNS servers, we send a query to the first one. dig +norecurse @E.GTLD-SERVERS.NET any gaia.cs.umass.edu

umass.edu. 172800 IN NS ns1.umass.edu. umass.edu. 172800 IN NS ns2.umass.edu. umass.edu. 172800 IN NS ns3.umass.edu.

Among all three returned authoritative DNS servers, we send a query to the first one. dig +norecurse @ns1.umass.edu any gaia.cs.umass.edu